[19bmwg05]

I recently purchased a 2009 328xi (N52) wagon from a private seller. The car has about 165k miles and I'm the second owner.

1. The previous/original owner said that they just had all of the pads and rotors done and upon research, the service interval said that there were still 16k miles left for the fronts. I tried to reset it, but before it could reset, the car chimed and the yellow service light came on (car on lift). I tried two more times after this and got the same outcome. I also tried to reset the service interval, but it didn't get rid of the yellow service light. I inspected the pads and the sensors and everything seems to be in good shape.

2. I have established that I need new TPM sensors as the warning light flashes and then becomes solid upon further driving. All of the tires are at their correct pressures and have good tread depth. In addition to this, the yellow "BRAKE" light is on and the hill start assist is not active. Could these two things be in relation to the bad TPM sensors? And if so, could this lead to any issues or problems to the xDrive system?

Other than that, the car is amazing and I love driving it. I've had numerous BMW's, but this is the first time that I'm working with an E9X without an iDrive system and the first time that I've owned an xDrive for myself. If any of you guys could help me out, that'd be much appreciated!!!

[gster109]

Originally Posted by 06bmwe90

I recently purchased a 2009 328xi (N52) wagon from a private seller. The car has about 165k miles and I'm the second owner.

1. The previous/original owner said that they just had all of the pads and rotors done and upon research, the service interval said that there were still 16k miles left for the fronts. I tried to reset it, but before it could reset, the car chimed and the yellow service light came on (car on lift). I tried two more times after this and got the same outcome. I also tried to reset the service interval, but it didn't get rid of the yellow service light. I inspected the pads and the sensors and everything seems to be in good shape.

2. I have established that I need new TPM sensors as the warning light flashes and then becomes solid upon further driving. All of the tires are at their correct pressures and have good tread depth. In addition to this, the yellow "BRAKE" light is on and the hill start assist is not active. Could these two things be in relation to the bad TPM sensors? And if so, could this lead to any issues or problems to the xDrive system?

Other than that, the car is amazing and I love driving it. I've had numerous BMW's, but this is the first time that I'm working with an E9X without an iDrive system and the first time that I've owned an xDrive for myself. If any of you guys could help me out, that'd be much appreciated!!!

There are brake wear sensors that need changing along side brake jobs.

Someone correct me if i'm wrong but i'm in the same boat and have come to that conclusion.

[Bimmer_Bro]

There is brake wear sensors on the passenger front and rear. However I am not a fan of these. They get tripped when you still have 40-50% pad left in my experience. When i did my brakes last I spliced the sensor wire and sod them together. I zip tied them out of the way. Being a car guy I would rather visually inspect my brakes vs those damn sensors.

Are you sure you have tps? There is also a system that uses the abs to detect if one wheel is spinning slower than the others. I had this trip on a road trip once. From some weird ruts in the road. I had to YouTube the procedure to clear the dash lights. Just a thought.

[Efthreeoh]

I'll not reprise it here, but the brake system uses "dual-stage" pad wear sensors so the CBS (condition-base service) system can estimate remaining pad life. Google "E90 Dual-stage brake sensor" and you should find a complete description on how the system works.

You don't indicate if the pad wear sensors were replaced at the brake refurbishment done by the PO. If the pad sensors were not replaced, or the CBS not reset at the time the brakes were done and then you tried to reset the system, you now have confused the CBS. The easy fix is to install new pad sensors (they are consumable items) and then reset the system. At 16,000 miles remaining, my bet is the sensors were replaced but the CBS was not reset, or the sensors were not replaced and the system was not reset, and you reset it early.

Despite what others will say on the subject, the brake pad wear system works perfectly if the brakes are serviced correctly by someone who understands how the system works. Tying off the sensors is stupid because the system has a fail safe that provides a pad wear warning once the second stage of the pad sensor is activated.

The pad sensors are one each for the front and rear brakes. The front sensor is on the driver's side (left side in the US) on the inside brake pad. The rear sensor is on the right side brake on the inside pad. Each sensor can be replaced with out disassembling the brake.

[19bmwg05]

Originally Posted by Bimmer_Bro

There is brake wear sensors on the passenger front and rear. However I am not a fan of these. They get tripped when you still have 40-50% pad left in my experience. When i did my brakes last I spliced the sensor wire and sod them together. I zip tied them out of the way. Being a car guy I would rather visually inspect my brakes vs those damn sensors.

Are you sure you have tps? There is also a system that uses the abs to detect if one wheel is spinning slower than the others. I had this trip on a road trip once. From some weird ruts in the road. I had to YouTube the procedure to clear the dash lights. Just a thought.

The pad sensors on my E90 and my E91 are front driver and rear passenger. Maybe this is different on your car? And yes, I have the TPS because I have the ability to reset the system. I've come to believe that there is a bad sensor because the reset setting says "INACTIVE" when I tried to reset after properly inflating.

[19bmwg05]

Originally Posted by Efthreeoh

I'll not reprise it here, but the brake system uses "dual-stage" pad wear sensors so the CBS (condition-base service) system can estimate remaining pad life. Google "E90 Dual-stage brake sensor" and you should find a complete description on how the system works.

You don't indicate if the pad wear sensors were replaced at the brake refurbishment done by the PO. If the pad sensors were not replaced, or the CBS not reset at the time the brakes were done and then you tried to reset the system, you now have confused the CBS. The easy fix is to install new pad sensors (they are consumable items) and then reset the system. At 16,000 miles remaining, my bet is the sensors were replaced but the CBS was not reset, or the sensors were not replaced and the system was not reset, and you reset it early.

Despite what others will say on the subject, the brake pad wear system works perfectly if the brakes are serviced correctly by someone who understands how the system works. Tying off the sensors is stupid because the system has a fail safe that provides a pad wear warning once the second stage of the pad sensor is activated.

The pad sensors are one each for the front and rear brakes. The front sensor is on the driver's side (left side in the US) on the inside brake pad. The rear sensor is on the right side brake on the inside pad. Each sensor can be replaced with out disassembling the brake.

I agree with you on the pad sensors. The only time I have had a problem with these is on an E39 when I first started working on cars. I pulled the wire too far, and accidentally nicked the wire past the sensor plug.

I looked at the pads and they seem to be okay. I figured it wasn't a pad because I don't have the yellow brake pad light yet. I was unaware of the dual-stage sensors though, so that might be the cause of the yellow "BRAKE" like on the dash. I'll pull the wheels off sometime this week if I have the time.